text: from cytracepy.io import read_cell_x_branch, read_feature_matrix, read_markers
  import io
  import pandas as pd
  
  feature_matrix = "\ta\tb\tc\n" +\
                   "1\t1\t2\t3\n" +\
                   "2\t1\t2\t3\n"
  
  cell_x_branch = "b1\tb2\n" +\
                  "1\t1\t.7\n" +\
                  "2\t2.3\t5\n"
  
  gmt = "b1\t\ta\tb\tc\n"+\
        "b2\t\td\tz\tf\t\n"
  
  def test_gmt_is_dict():
      fh = io.StringIO(gmt)
      marker_dict = read_markers(fh)
      assert type(marker_dict) == dict
  
      
  def test_gmt_keeps_order():
      fh = io.StringIO(gmt)
      marker_dict = read_markers(fh)
      assert marker_dict["b1"][1] == "b" 
  
  def test_gmt_2():
      fh = io.StringIO(gmt)
      marker_dict = read_markers(fh)
      assert marker_dict["b2"][2] == "f" 
  
  def test_cxb_is_dataframe():
      fh = io.StringIO(gmt)
      cxb = read_cell_x_branch(fh)
      assert type(cxb) == pd.DataFrame 
  
  def test_feature_is_dataframe():
      fh = io.StringIO(gmt)
      fmat = read_feature_matrix(fh)
      assert type(fmat) == pd.DataFrame